GCOS activities and interests in any nation normally cut across many departments and agencies in that nation, rather than being limited to one agency, such as a meteorological service. It is therefore desirable and efficient for GCOS to have, if possible, a single contact in each nation who can coordinate amongst the relevant agencies and represent the views of all, or at least most, of them on a regular basis. This is the role envisaged for a "GCOS National Coordinator".
Download their Terms of Reference.
Download a list of GCOS National Coordinators.